Describe the issue
file configmap provider assumes all relative URLs as relative paths from the current directory.

When a URL refers a file in other directory and it contains ${file:xxx.yaml} expression, the collector will search xxx.yaml always in the current directory.

Is it by design?

Steps to reproduce
I constructed file tree as below:

$ ls otelcol-contrib
otelcol-contrib

$ ls configs
config.yaml  exporters.yaml

configs/config.yaml

exporters: ${file:exporters.yaml}

receivers:
  otlp:
    protocols:
      grpc:

service:
  pipelines:
    traces:
      receivers: [otlp]
      exporters: [otlp]

configs/exporters.yaml

otlp:
  endpoint: localhost:4317

Then, I ran otelcol-contrib with --config=file:configs/config.yaml

UPDATED: 2023-06-09

$ ./otelcol-contrib --config=file:configs/config.yaml
Error: failed to get config: cannot resolve the configuration: unable to read the file file:exporters.yaml: open exporters.yaml: no such file or directory
2023/06/09 22:24:59 collector server run finished with error: failed to get config: cannot resolve the configuration: unable to read the file file:exporters.yaml: open exporters.yaml: no such file or directory

I ran below after change current directory to configs.

$ ../otelcol-contrib --config=file:config.yaml
... otelcol-contrib launches successfully ...

What did you expect to see?

I expect the collector reads configs/config.yaml and configs/exporters.yaml then it will launch successfully.

In my opinion, it is more commonplace if a config file refer to other config files, parent config file search a file from a directory that parent config is stored in, like #include of C.

What did you see instead?

unable to read the file file:config/config.yaml: open config/config.yaml: no such file or directory

What version did you use?
Version: v0.79.0

What config did you use?
Config: I described it above

Environment
OS: Arch Linux
Compiler(if manually compiled): I downloaded it from releases

Additional context
Add any other context about the problem here.